An edgewise wound coil formed by winding a flat wire is manufactured, for example, using a magnetic field coil manufacturing device disclosed in Patent Document 1. The manufacturing device disclosed in Patent Document 1 includes a core around which a flat wire is wound, a first driving part for rotating the core, a guide for guiding the flat wire when it is wound, a second driving part for pressing the guide against the core, a third driving part for moving the core or the guide in an axial direction of the core, and a base for movably supporting the first, second and third driving parts. According to this manufacturing device, the first driving part rotates the core, and the second driving part brings the guide into contact with the core. The flat wire is pressed against a surface of the core by the guide and the flat wire is wound around the core. Simultaneously, the third driving part moves the core or the guide in the axial direction of the core. Therefore, the flat wire is pressed against the surface of the core and in this state, the flat wire is helically wound. As a result, the edgewise wound coil formed by winding the flat wire in a cylindrical shape is manufactured.
An edgewise wound coil formed by winding the flat wire in a polygonal shape is also manufactured. To manufacture such an edgewise wound coil, a manufacturing method of a polygonal coil described in Patent Document 2 is employed, for example. The manufacturing method of Patent Document 2 uses a polygonal core, which has two opposed surfaces with recesses, and a pressure roller arranged to face the recesses of the core. The pressure roller is pressed against the core by a spring or a hydraulic system.
When the coil is formed, a thin conductor (flat wire) is wound around the core while being pressed by the pressure roller against the core. At this time, portions of the thin conductor that corresponds to the recesses are depressed toward the core, and depressed parts of the coil are formed. When the core is pulled out of the coil, an edgewise wound coil formed by winding the thin conductor in a polygonal shape is manufactured. In the manufacturing method of Patent Document 2, since the depressed parts of the coil cancel or compensate for swells of the coil, which are generated after the core is pulled out, a coil is manufactured in which its straight part between angle portions of the coil extends in a straight manner.